The permeability characteristics of the pulmonary capillary membrane will be studied in both isolated and intact dog lungs by measuring the reflection coefficient and PS products of the various protein fractions in lung lymph. These permeability measurements will be coupled with the measurement of various tissue forces (tissue fluid pressure, tissue colloid osmotic pressure and lymph flow) in lungs made edematous by various experimental procedures, e.g. hydrostatic pressure increases, "shock lung," drug infusions, etc. The intact lung model will allow us to differentiate between the various forms of edema caused by capillary permeability changes and those caused by change in pulmonary tissue forces. Finally, a comprehensive model will be developed that considers the difference in capillary pressures and tissue forces at different lung levels and how these tissue forces are altered during the formation of pulmonary edema. BIBLIOGRAPHIC REFERENCES: Conwill, D.E., D.N. Granger, B.H. Cook and A.E. Taylor. The relationship between serum cholesterol and serum albumin in "normal" adults. IRCS 4:304, l976. Cook, B.H., R.E. Parker, D.N. Granger, H.J. Granger and A.E. Taylor. Histochemistry of non-alveolar pulmonary tissue. Physiol. l976.